But unlike conventional cybercriminals, the agency is less interested in hacking PCs and Macs. Instead, America’s spooks have their eyes on the internet routers and switches that form the basic infrastructure of the net, and are largely overlooked as security vulnerabilities.

Under a $652-million program codenamed “Genie,” U.S. intel agencies have hacked into foreign computers and networks to monitor communications crossing them and to establish control over them, according to a secret black budget document leaked to the Washington Post. U.S. intelligence agencies conducted 231 offensive cyber operations in 2011 to penetrate the computer networks of targets abroad.